It has been found that, in this application, a given number of tear faults were observed along the notch. These faults were attributed to the fact that, when the trim component is formed by means of foaming a plastics material in contact with the skin, the plastics material penetrates into the notch and forms a practically continuous bridge over at least a significant portion of the depth of the notch. The notch therefore loses its functionality, since the connection provided by the plastics material between the two sides of the notch may be stronger the one which the material of the skin itself would provide without a notch.